Pool swim season in El Centro, CA
El Centro, CA: how long the pool season really is
An unheated pool in El Centro reaches 78°F in May to Oct, about 6 months a year. The air allows up to 11 swimmable months with a heater (Jan to Nov).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
What each heater buys you in El Centro
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 6 | May to Oct | $0 | $0 |
| Solar cover only | 7 | Apr to Oct | $0 | $50 |
| Solar panels + cover | 9 | Mar to Nov | $0 | $283 |
| Heat pump + cover | 11 | Jan to Nov | $836 | $1,386 |
| Gas heater + cover | 11 | Jan to Nov | $1,064 | $1,489 |
For a 450 sq ft pool held at 80°F, at CA prices of 32.6¢/kWh electricity and $22/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in El Centro
Heat pump + cover: 11 of 11 possible months for about $1,386 a year all-in, which works out near $277 for each month it adds.
Before you pay for any heater, buy a solar cover: on its own it adds 1 month here for about $50 a year (why a cover comes first). If you get quotes, ask for a heat pump sized to your pool's surface area; here it beats gas all-in (heat pump or gas).
Weather station: El Centro 2 SSW, 1.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
El Centro month by month: air, sun and pool water
| Month | Air high | Air avg | Sun kWh/m²/day | Water, unheated | Water, covered | Heat pump $ | Gas $ |
|---|---|---|---|---|---|---|---|
| Jan | 71° | 57° | 3.6 | 57° | 63° | $351 | $427 |
| Feb | 74° | 60° | 4.5 | 60° | 66° | $275 | $350 |
| Mar | 80° | 66° | 6.0 | 66° | 72° | $148 | $202 |
| Apr | 86° | 72° | 7.3 | 73° | 79° | $18 | $26 |
| May | 94° | 79° | 8.1 | 80° | 86° | – | – |
| Jun | 103° | 87° | 8.4 | 88° | 94° | – | – |
| Jul | 107° | 93° | 7.7 | 94° | 100° | – | – |
| Aug | 107° | 93° | 7.2 | 97° | 103° | – | – |
| Sep | 102° | 88° | 6.3 | 94° | 100° | – | – |
| Oct | 92° | 77° | 5.1 | 84° | 90° | – | – |
| Nov | 79° | 65° | 3.9 | 72° | 78° | $44 | $59 |
| Dec | 70° | 56° | 3.2 | 61° | 67° | – | – |
Heating costs most in Jan (about $351 with a heat pump, $427 with gas). Sunshine peaks in Jun at 8.4 kWh/m²/day (NASA satellite data, 32.3 km grid cell). Highlighted months are swimmable with no heater.
How El Centro compares with nearby cities
El Centro ranks 9 of 376 California cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Imperial, CA | 4 mi | 6 | 11 | $951 |
| Calexico, CA | 8 mi | 6 | 11 | $836 |
| Brawley, CA | 13 mi | 6 | 12 | $1,201 |
| Somerton, AZ | 52 mi | 6 | 10 | $174 |
| San Luis, AZ | 53 mi | 6 | 10 | $174 |
| Yuma, AZ | 63 mi | 6 | 10 | $174 |